In modern traffic control technology it is often required that traffic lanes and access roads be temporarily redirected or closed to traffic during certain peak traffic hours. This control is accomplished by setting in the roadway control devices indicating the traffic flow desired. In the past these devices have been set in the road by hand or more recently raised by pneumatic means from a remote site.
The shortcomings of the hand setting method are obvious in that the method requires a substantial amount of time for extensive control systems and, in addition poses a hazard to those placing the devices. The pneumatic devices, exemplified by the devices disclosed in U.S. Pat. Nos. 3,530,775 and 3,447,429, require close clearances within the device to prevent excessive air leakage and are subject to contamination by road dirt and sand, ice and snow and other debris often deposited on the highway. In addition, the installation of pneumatic lines in the road is a costly and time consuming procedure.